This invention relates in general to heading machinery and deals more specifically with an improved rotary machine for continuous operation to form a succession of headed workpieces or fasteners such as nails from preformed axially elongate workpieces such as cut wire nail blanks.
A typical machine of the type with which the present invention is concerned is illustrated and described in International Application Publications No. WO 89/03734 and WO 89/03735, both published May 5, 1989, and has a rotary holding ring assembly for receiving and holding a succession of workpieces or nail blanks in radially disposed position while continuously advancing the blanks along a circular path. A forming roller disposed within the ring assembly and in the path of advancing nail blanks engages and upsets radially inwardly projecting end portions of the advancing nail blanks to form heads thereon. The holding ring assembly includes a pair of opposing holding rings journalled for rotation in side-by-side relation about mutually inclined intersecting axes. The holding rings carry a plurality of sets of opposing dies for wedgingly clamping each nail blank therebetween as the blank, which is clamped to one of the rings, moves through a forming station where the upsetting or head forming operations are performed.
In a machine of the aforesaid type, a nail blank is injected in a radial direction from a stationary position toward and into holding clamps at each blank receiving station on the rotating ring assembly. At each blank receiving station there is only a small "window" opening, through which a blank can be injected as the station passes the injecting position. This arrangement requires extremely fast blank injection speed. In general, very accurate machine tuning is required to avoid malfunction. In actuality this difficulty in machine tuning is usually overcome by running the machine at a lower speed, thereby sacrificing production.
The machine illustrated in the aforesaid application publications has a holding ring assembly which includes thirty six nail receiving stations and carries thirty six separate sets of nail forming dies and thirty six separate holding clamps. The die sets must be changed and the clamps adjusted or changed each time the machine is set up to form a different size fastener, which results in considerable machine down time.
It is the general aim of the present invention to provide an improved machine of the aforedescribed generally type capable of continuous high speed operation at a relatively low noise level and having simplified tooling which may be rapidly adjusted to form headed workpieces such as nails or like fasteners in a range of sizes with minimal machine downtime.